# Perplexity

> An AI answer engine that searches the web and replies with a summary and its sources.

- Level: Basic
- Topics: Tech companies, AI
- URL: https://tidbit.legios.com.ar/perplexity/
- In Spanish: [Perplexity](https://tidbit.legios.com.ar/es/perplexity/)

**Perplexity** is an American company founded in 2022 in San Francisco by Aravind Srinivas, Denis Yarats, Johnny Ho and Andy Konwinski. Its product, also called Perplexity, calls itself an **answer engine**: instead of returning a list of blue links like a classic search engine, it returns a written answer to your question.

Under the hood it combines a search engine with a large language model. When you ask something, Perplexity searches the web, picks the most relevant pages, reads them and asks the model to write an answer based only on what it found, with **numbered citations** pointing to each source so you can check them. This technique is known as RAG (retrieval-augmented generation). It can use its own models or models from other companies, such as OpenAI and Anthropic, and lets paying users choose.

It makes money mainly through subscriptions: a free version with limits and paid plans for individuals and companies, plus an API for developers. Like other AI search tools, it raises a fair question about the open web: some news publishers have objected to how it uses their articles, since readers may get the answer without ever visiting the page that produced it.

## An analogy

A research assistant who, when you ask a question, goes to the library, skims the relevant books and comes back with a one-page summary that has footnotes on every claim.

## Keep in mind

- Founded in 2022 in San Francisco; its product is also called Perplexity.
- Searches the web, then has an LLM write an answer with numbered sources.
- Uses its own models and models from other AI companies.
- Makes money from subscriptions and an API for developers.

## Go deeper

- [Perplexity Help Center (official)](https://www.perplexity.ai/help-center/en)
- [Perplexity AI on Wikipedia](https://en.wikipedia.org/wiki/Perplexity_AI)

## Related terms

- [LLM](https://tidbit.legios.com.ar/llm/): A neural network trained on huge amounts of text to predict the next word.
- [RAG](https://tidbit.legios.com.ar/rag/): Let the model look things up in your documents before it answers.
- [OpenAI](https://tidbit.legios.com.ar/openai/): The company that made ChatGPT and turned AI into a household topic.
- [Anthropic](https://tidbit.legios.com.ar/anthropic/): The AI company behind Claude, built around making models safe and useful.
- [API](https://tidbit.legios.com.ar/api/): The menu of things one program lets another program ask for.
- [Artificial intelligence](https://tidbit.legios.com.ar/artificial-intelligence/): Getting computers to do things that, until recently, only people could do.